Immersion cooling enclosures with insulating liners

ABSTRACT

Immersion cooling enclosures with insulating liners and associated computing facilities are disclosed herein. In one embodiment, an immersion cooling enclosure includes a well formed in a substrate material, a lid in contact with and fastened to the well to enclose an internal space configured to contain a dielectric coolant submerging one or more computing devices in the internal space, and an insulating liner on the internal surfaces of the well. The insulating liner has a first side in contact with the dielectric coolant and a second side in contact with the substrate material of the well. The insulating liner is non-permeable to the dielectric coolant, thereby preventing the dielectric coolant from passing through the insulating liner to the substrate material.

BACKGROUND

Large computing facilities such as datacenters typically include adistributed computing system housed in large buildings, containers, orother suitable enclosures. The distributed computing system can containthousands to millions of servers interconnected by routers, switches,bridges, and other network devices. The individual servers can hostvirtual machines, containers, virtual switches, virtual routers, orother types of virtualized devices. Such virtualized devices can be usedto execute applications or perform other functions to facilitateprovision of cloud computing services to users.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Servers in datacenters typically include one or more central processingunits (“CPUs”), graphic processing units (“GPUs”), solid state drivers(“SSDs”), memory chips, etc. mounted on a printed circuit board to forma “server.” CPUs, GPUs, and other components of a server can producesignificant amount of heat during operation. If not adequatelydissipated, the produced heat can damage and/or degrade performance ofthe various components on the server.

Various techniques using air cooling have been developed to dissipateheat produced by components of servers. For example, one techniqueincludes placing a fan in a server enclosure (e.g., at a top or bottomof a cabinet) to force cool air from outside of the server enclosureinto contact with heat producing components on servers to remove heat tothe outside of the server enclosure. In another example, intercoolers(e.g., cooling coils) can be positioned between sections of servers inthe server enclosure. The intercoolers can remove heat from groups ofthe servers in a server enclosure and generally maintain the cooling airat certain temperature ranges inside a server enclosure.

The foregoing air cooling techniques, however, have certain drawbacks.First, air cooling can be thermodynamically inefficient when compared toliquid cooling. Heat transfer coefficients of conduction and/orconvection with air and specific heat of air as a heat transfer mediumcan be an order of magnitude below with water, ethylene glycol, or othersuitable types liquid. As such, due to limitation on heat removal,densities of heat producing components (e.g., CPUs and GPUs) on a servermotherboard can be limited. In addition, air cooling can have long lagtimes in response to a control adjustment and/or load change. Forexample, when a server enclosure has a temperature exceeds a threshold,additional flow of cooling air can be introduced into the serverenclosure to reduce the temperature. However, due to slow thermaltransfer rates of cooling air, the temperature in the server enclosuremay stay above the threshold for quite a long time.

Immersion cooling techniques can address at least some of the foregoingdrawbacks of air cooling. Immersion cooling generally refers to acooling technique according to which components such as CPUs, GPUs,SSDs, memory, and/or other electronics components of a server aresubmerged in a thermally conductive but dielectric liquid (referred toherein as a “dielectric coolant”). Example dielectrics coolants caninclude mineral-oils or synthetic chemicals. Such dielectric coolantscan have dielectric constants like that of ambient air. For example, adielectric coolant provided by 3M (Electronic Liquid FC-3284) has adielectric constant of 1.86 while that of ambient air at 25° C. is about1.0.

In certain implementations, during operation, the dielectric coolant canremove heat from the heat producing components via boiling of thedielectric coolant by undergoing a phase change of the liquid dielectriccoolant into a dielectric vapor, resulting in both liquid and gaseousphases of the dielectric coolant within a server enclosure. Thedielectric vapor can then be cooled and condensed back to a liquid formvia a circulation system employing liquid pumps, heat exchangers, drycoolers, etc. to reject heat from the dielectric coolant into thesurrounding environment. In other implementations, the dielectriccoolant can stay in a single-phase during operation. Due to high heattransfer coefficients and specific heat properties of using thedielectric coolant, densities of heat producing components in a serverenclosure may be increased. Higher densities of CPUs, GPUs, etc. canresult in smaller footprint for datacenters, racks, server enclosures,or other suitable types of computing facilities. High heat transfercoefficients of using the dielectric coolant can also allow fast cooldown of sever components in a server enclosure.

One example design of an immersion cooling enclosure includes anelongated container (e.g., a 10-foot long container commonly referred toas a “tank”) housing multiple servers mounted vertically in the tank.The tank is typically constructed with welded stainless-steel plates ina rectilinear shape. Such a design for the immersion cooling enclosure,however, can have high engineering, manufacturing, and constructioncosts. For example, stainless steel plates can be expensive to acquireand costly to process. Welding stainless steel plates together requiresspecial skills and is labor intensive. Also, once welded, the tanktypically requires conformance testing, such as using helium, todetermine whether any leak exists in the welds or pressure testing. Oncetested, the tank is typically installed on a support structure in afacility. As such, deploying immersion cooling enclosures with such asdesign can have long lead time and can be capital intensive.

Several embodiments of the disclosed technology can address at leastsome of the drawbacks of the welded stainless-steel design byimplementing an insulated-well design for an immersion coolingenclosure. In certain implementations, the immersion cooling enclosurecan include a well, pit, hole, or other suitable types of indentation(referred to herein as a “well” for illustration purposes) formed inconcrete, earth, bricks, or other suitable types of a substrate materialand lined with an insulating liner. In one example, a well can be formedby excavating a portion of the ground (e.g., earth) in a facility toform a rectilinear pit and then pouring concrete to line the excavatedportion of the ground to form a concrete well. In other examples, a wellcan be formed by placing one or more pre-fabricated concrete blocks onthe ground in the facility to form a rectilinear well. In furtherexamples, a well can be formed by surrounding a portion of the groundwith earth, concrete, or other suitable materials to form anabove-ground well. In yet further examples, a well can be formed inother suitable manners.

Without being bound by theory, the inventors have recognized that adielectric coolant typically have small molecular sizes and thus cangenerally permeate through concrete and earth. As such, in order to atleast reduce or avoid leaking the dielectric coolant from the wellthrough concrete or earth, several embodiments of the disclosedtechnology are directed to lining the well with the insulating linerthat is non-permeable to the dielectric coolant. In one embodiment, theinsulating liner can include a single insulating layer of high-densitypolypropylene (HDPP), high-density polyethylene (HDPE), or othersuitable types of non-permeable polymeric material.

In other embodiments, the insulating liner can also include multiplelayers arranged in a stack, interweaving, or other suitable manners. Forexample, the insulating liner can include an insulating layer (e.g.,HDPP or HDPE) sandwiched between a protection layer facing thedielectric coolant and a sealing layer opposite the protection layer.The protection layer can include one or more protection materialsconfigured to protect the insulating layer from perforation, scraping,or other suitable types of mechanical damages caused by, for instance,contact with servers during installation or maintenance. Examples ofsuitable protection materials can include Nylon, Kevlar, ultra-highmolecular weight polyethylene, silk, carbon fibers, or combinations ofat least some of the foregoing protection materials. The sealing layercan include one or more sealing materials that are configured toautomatically seal the insulating layer in case of a perforation isformed in the insulating layer. Examples of suitable sealing materialscan include ballistic gelatins, multiple strata of rubber coating, orother suitable sealant that can automatically expand and/or contract toseal a perforation.

In further embodiments, the insulating liner can also include aperfusion layer configured to remove and thus allow detections of anyleaked dielectric coolant through the insulating layer. For example, aperfusion layer can include a base having multiple ribs or othersuitable types of protrusions extending from the base. Adjacent pairs ofthe multiple ribs can then form multiple channels in fluid communicationwith a vacuum source. As such, when the perfusion layer is positionedbehind and/or attached to the insulating layer, with or withoutintermediate layer(s), any leaked dielectric coolant can be removed frombehind the insulating layer. By monitoring output from the perfusionlayer, leak detection of the dielectric coolant from the well can beachieved using color changing paints, sensors, or other suitabledetectors. In other examples, the perfusion layer can also include a topopposite the base such that the multiple ribs extend between the top andthe base. In further examples, the perfusion layer can be a built-inlayer at the insulating layer, sealing layer, or other suitable layersof the insulating liner.

In certain implementations, the insulating liner can be formed viaextrusion and fastened to an internal surface of the well withadhesives, mechanical fasteners, or other suitable fasteners. In otherimplementations, one or more of the protection, insulating, sealing, orother suitable types of layer may be sprayed on or otherwise formeddirectly on the internal surface of the well or a preceding layer of theinsulating liner. In further implementations, the insulating liner canbe formed via vacuum forming, friction welding, sonic welding, or othersuitable techniques.

The immersion cooling enclosure can also include a lid, cover, top, orother suitable closure component (referred to herein as “lid” forbrevity) that is configured to mate with and seal against the well usingone or more O-rings, gaskets, or other suitable sealing devices. The lidcan include various components that are configured to facilitateimmersion cooling operations in the well. For example, the lid caninclude a condenser (e.g., a cooling coil) configured to condense adielectric vapor in a vapor space in the well. The lid can also includesuitable conduits, pipes, tubings, etc. to provide a cooling fluid(e.g., cooling water) to the condenser and power/signal to the servers.In other examples, the lid can also include pressure sensors,temperature sensors, sight glasses, or other suitable componentsconfigured to facility monitoring, controlling, or other suitableoperations of the immersion cooling enclosure.

In further examples, the lid can also include a filter layer that ispermeable by air but not the dielectric vapor. An example materialsuitable for the filter layer includes activated carbon. The filterlayer can be position between a vapor space in the well and a vaporoutlet to the external environment. As such, air may bewithdrawn/introduced from/to the vapor space of the well to controlpressure in the well without losing a large amount of dielectric vapor.The withdrawn air can also be further condensed to recover anydielectric coolant still present and return to a collection reservoirand/or the well via, for instance, a circulation pump. In yet furtherexamples, multiple filter layers and/or condensers may be arranged insequence, interleaved, or other suitable manners between the vapor spaceand the vapor outlet.

During installation, a rack or other suitable types of supporting devicecan be placed inside the well. The rack can also include a protectionlayer at surfaces that contact or come near the well. One or moreservers can be placed in the rack. The well is then covered with the lidand sealed. The dielectric coolant is then introduced into the well tofully submerge the servers carried on the rack. During operation, CPUs,GPUs, and other suitable components on the servers can produce heat. Thedielectric coolant can absorb the produced heat via boiling byundergoing a phase change to form a dielectric vapor. The dielectricvapor rises in the well to be in contact with the condenser at orattached to the lid. The cooling fluid circulating in the condenser thenremoves heat from the dielectric vapor and condenses the dielectricvapor into liquid form. The condensed dielectric vapor is then returnedto the well via gravity or pump.

Several embodiments of the disclosed immersion cooling enclosure canhave lower capital costs and manufacturing complexity than weldingstainless steel plates. Unlike in welded tanks, sealing of the immersioncooling enclosure in accordance with the disclosed technology does notrely on welds between stainless steel plates. Instead, sealing isachieved via the insulating liner. Because the insulating liner is not astructural member, engineering and constructing the immersion coolingenclosure can be much simplified than welded stainless steel tanks. Assuch, costs of engineering, manufacturing, construction, and othersuitable types of capital costs can be significantly lowered whencompared to using welded stainless-steel tanks as immersion coolingenclosures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a computing facility having animmersion cooling enclosure of an insulated-well design that isconfigured in accordance with embodiments of the disclosed technology.

FIGS. 2A-2C are schematic cross-sectional views of an insulating linersuitable for the immersion cooling enclosure in FIG. 1 in accordancewith embodiments of the disclosed technology.

FIG. 3 is schematic cross-sectional view of a lid suitable for theimmersion cooling enclosure in FIG. 1 in accordance with additionalembodiments of the disclosed technology.

FIG. 4 is a flowchart illustrating an example process of deploying animmersion cooling enclosure of the insulated-well design of FIG. 1 inaccordance with embodiments of the disclosed technology.

DETAILED DESCRIPTION

Certain embodiments of computing facilities, systems, devices,components, modules, and processes for immersion cooling enclosures ofan insulated-well design are described below. In the followingdescription, specific details of components are included to provide athorough understanding of certain embodiments of the disclosedtechnology. A person skilled in the relevant art can also understandthat the disclosed technology may have additional embodiments or may bepracticed without several of the details of the embodiments describedbelow with reference to FIGS. 1-4.

As used herein, the term an “immersion server enclosure” generallyrefers to a housing configured to accommodate a server, server, or othersuitable types of computing device submerged in a dielectric coolantinside the housing during operation of the server. A “dielectriccoolant” generally refers to a liquid that is thermally conductive butdielectric. Example dielectrics coolants can include mineral-oils orsynthetic chemicals. Such a dielectric coolant can have a dielectricconstant that is generally like that of ambient air (e.g., within 100%).For example, a dielectric coolant provided by 3M (Electronic LiquidFC-3284) has a dielectric constant of 1.86 while that of ambient air at25° C. is about 1.0. In certain implementations, a dielectric coolantcan have a boiling point low enough to absorb heat through a phasechange from operating electronic components (e.g., CPUs, GPUs, etc.).For instance, Electronic Liquid FC-3284 provided by 3M has a boilingpoint of 50° C. at 1 atmosphere pressure.

Immersion cooling of servers can have many advantages when compared toair cooling. For example, immersion cooling can be morethermodynamically efficient due to higher heat transfer coefficients.However, current designs of immersion cooling enclosures may not besuitable for fast and cost-effective deployment. For example, one designfor immersion cooling enclosures includes welding stainless steel platesinto an elongated container or “tank.” Such a design for the immersioncooling enclosures, however, can have high engineering, manufacturing,and construction costs. For example, stainless steel plates can beexpensive to acquire and costly to process. Welding stainless steelplates together requires special skills and is labor intensive. Also,once welded, the tank typically requires conformance testing, such asusing helium, to determine whether any leak exists in the welds orpressure testing. Once tested, the tank is typically installed on asupport structure t in a facility. As such, deploying immersion coolingenclosures with such as design can have long lead time and can becapital intensive.

Several embodiments of the disclosed technology can address at leastsome of the drawbacks of the welded stainless-steel design byimplementing an insulated-well design for an immersion coolingenclosure. In certain embodiments, the immersion cooling enclosure caninclude a well formed in concrete, earth, bricks, or other suitabletypes of a substrate material and lined with an insulating liner. Theinsulating liner can include an insulating layer that is configured toprevent the dielectric coolant from permeating through the insulatinglayer and leak from the immersion cooling enclosure. Example materialssuitable for the insulating layer can include high-density polypropylene(HDPP), high-density polyethylene (HDPE), or other suitable types ofnon-permeable polymeric material. Thus, the insulating liner can be usedto prevent loss of the dielectric coolant from the immersion coolingenclosure without being a structural member of the well. As such,capital costs for deploying immersion cooling enclosures can be reducedwhen compared to using welded stainless-steel tanks as immersion coolingenclosures, as described in more detail below with reference to FIGS.1-4.

FIG. 1 is a schematic diagram of a computing facility 100 having animmersion cooling enclosure 106 of an insulated-well design that isconfigured in accordance with embodiments of the disclosed technology.As shown in FIG. 1, the computing facility 100 can include an immersioncooling enclosure 102 in which a rack 101 carrying multiple servers orservers (referred to herein as “servers 103” for brevity) are installed.Each of the servers 103 can include one or more heat producingcomponents 105, such as CPUs, GPUs, etc. The computing facility 100 canalso include a circulation pump 114 and a cooling tower 116 operativelycoupled to the immersion cooling enclosure via an inlet manifold 112 aand an outlet manifold 112 b. Even though only one immersion coolingenclosure 102 is shown in FIG. 1 for illustration purposes, in otherembodiments, the computing facility 100 can include multiple immersioncooling enclosures 102 (not shown) arranged in parallel and coupled tothe same inlet and outlet manifolds 112 a and 112 b, and/or othersuitable components.

The circulation pump 114 can be configured to receive a cooling fluidfrom the immersion cooling enclosure 102 via the outlet manifold 112 band forward the received cooling fluid to the cooling tower 116. Thecooling tower 116 can then remove heat from the cooling fluid andprovide the cooling fluid to the immersion cooling enclosure 102 via theinlet manifold 112 a. The circulation pump 114 can include a centrifugalpump, a piston pump, or other suitable types of pump. Though particularconfiguration for cooling fluid circulation and cooling is shown in FIG.1, in other embodiments, the computing facility 100 can also includeadditional and/or different components. For example, the computingfacility 100 can include a chiller, one or more heat exchangers (notshown), and/or other suitable mechanical components.

As shown in FIG. 1, the immersion cooling enclosure 102 can include awell 104 formed in a substrate material (e.g., concrete or earth). Theformed well 102 can include an internal surface formed by a firstsurface 104 a at a first elevation, a second surface 104 b at a secondelevation lower than the first elevation, and side surfaces 104 cextending between the first and second surfaces 104 a and 104 b. In theillustrated example in FIG. 1, the side surfaces 104 c extend generallyperpendicularly between the first and second surfaces 104 a and 104 b.In other examples, one or more of the side surfaces 104 c can be cantedrelated to the first and/or second surfaces 104 a and 104 b.

In one implementation, the well 104 can be formed by excavating aportion of the ground (e.g., earth) in the computing facility 100 toform a rectilinear shape and a suitable size and then pouring concreteto line the excavated portion of the ground to form a concrete well 104.In other implementations, the well 104 can be formed by placing one ormore pre-fabricated concrete blocks on the ground in the computingfacility 100 to form a rectilinear well. In further examples, the well104 can be formed by surrounding a portion of the ground with earth,concrete, or other suitable materials to form an above-ground well. Inyet further examples, the well 104 can be formed in other suitablemanners.

An insulating liner 106 can be in contact with and suitably attached tothe internal surface of the well 104 via adhesives, mechanicalfasteners, or other suitable means. The insulating liner 106 can includeat least an insulating layer 126 (shown in FIG. 2A) that isnon-permeable to a dielectric coolant 120 and thus prevent or at leastreduce a rate of the dielectric coolant 120 leaking through thesubstrate material of the well 104. Without being bound by theory, theinventors have recognized that the dielectric coolant 120 typically havesmall molecular sizes and thus can generally permeate through concreteand earth. As such, in order to at least reduce or avoid leaking thedielectric coolant 120 from the well 104 through concrete or earth,several embodiments of the disclosed technology are directed to liningthe well 104 with the insulating liner 106 that is non-permeable to thedielectric coolant 120. In one embodiment, the insulating liner 106 caninclude a single insulating layer 126 of high-density polypropylene(HDPP), high-density polyethylene (HDPE), or other suitable types ofnon-permeable polymeric material. In other embodiments, the insulatingliner 106 can also include multiple layers arranged in a stack,interweaving, or other suitable manners. In further embodiments, one ormore of the layers in the insulating liner 106 can also include one ormore fluid channels 136 (shown in FIG. 2B) that are configured to trapand/or capture any dielectric coolant 120 escaping from the well 104.Examples of such multi-layered insulating liner 106 are described inmore detail below with reference to FIGS. 2A-2C.

The immersion cooling enclosure 102 can also include a lid 108 that isconfigured to mate with and seal against the well 104 using one or moreO-rings, gaskets, or other suitable sealing devices (not shown). Forexample, as shown in FIG. 1, the lid 108 can include a plate-likestructure in contact with and fastened to the first surface 104 a of thewell 104. As such, the lid 108, the second surface 104 b of the well104, and the side surfaces 104 c of the well 104 enclose an internalspace configured to contain the dielectric coolant 120. In theillustrated example, the internal space includes a liquid space 122 aand a vapor space 122 b. In other examples, the internal space can besubstantially filled with the dielectric coolant 120 with little or novapor space 122 b.

In certain embodiments, the lid 108 can be constructed from concrete, ametal/metal alloy as a substrate that carries various components thatare configured to facilitate immersion cooling operations in the well104. For example, the lid 108 can include a condenser 110 (e.g., acooling coil) in thermal communication with the vapor space 122 b andconfigured to condense a vapor of the dielectric coolant 120 in thevapor space 122 in the well 104. In the illustrated embodiment, thecondenser 110 is shown as being attached to a side of the lid 108 facingthe well 104. In other embodiments, the condenser 110 can also beembedded into the lid 108 or having other suitable configurations. Thelid 108 can also include suitable conduits, pipes, tubings, etc. toprovide a cooling fluid (e.g., cooling water) to the condenser 110 andpower/signal to the servers 103. In other embodiments, the lid 108 canalso include pressure sensors, temperature sensors, sight glasses, orother suitable components (not shown) configured to facility monitoring,controlling, or other suitable operations of the immersion coolingenclosure 102.

In operation, heat producing components 105 of the servers 103 in theimmersion cooling enclosure 102 can consume power from a power source(not shown, e.g., an electrical grid) to execute suitable instructionsto provide desired computing services. The dielectric coolant 120 canabsorb the heat produced by the components 105 during operation andeject the absorb heat into the cooling fluid flowing through thecondenser 110. In certain embodiments, the dielectric coolant 120absorbs the heat produced by the servers 103 via a phase transition,i.e., evaporating a portion of the dielectric coolant 120 into a vaporand evaporate into the vapor space 122. The evaporated vapor can then becondensed by the cooling fluid flowing through the condenser 110 via theinlet manifold 112 a into a liquid and return to the well 104 viagravity (as illustrated by the dashed arrow) or pump. In otherembodiments, the dielectric coolant 110 can absorb the heat without aphase change. The circulation pump 114 then forwards the heated coolingfluid from the outlet manifold 112 b to the cooling tower 116 fordiscarding the heat to a heat sink (e.g., the atmosphere). The coolingfluid is then circulated back to the immersion cooling enclosure 102 viathe inlet manifold 112 a.

Several embodiments of the immersion cooling enclosure 102 can thus havelower capital costs and manufacturing complexity than welding stainlesssteel plates. Unlike in welded tanks, sealing of the immersion coolingenclosure 102 in accordance with the disclosed technology does not relyon welds between stainless steel plates. Instead, sealing is achievedvia the insulating liner 106. Because the insulating liner 106 is not astructural member, engineering and constructing the immersion coolingenclosure can be much simplified than welded stainless steel tanks. Assuch, costs of engineering, manufacturing, construction, and othersuitable types of capital costs of the immersion cooling enclosure 102can be significantly lowered when compared to using weldedstainless-steel tanks as immersion cooling enclosures.

FIGS. 2A-2C are schematic cross-sectional views of an insulating liner106 suitable for the immersion cooling enclosure 102 in FIG. 1 inaccordance with embodiments of the disclosed technology. As shown inFIG. 2A, an example insulating liner 106 can include a protection layer124 at a first side 106 a in contact with the dielectric coolant 120, aninsulating layer 126, a sealing layer 128, and a perfusion layer 130 ata second side 106 b in contact with substrate material at the internalsurface of the well 104 arranged in a stacked formation. In certainembodiments, the various layers shown in FIG. 2A can be formed viaextrusion. In other embodiments, the various layers can be sprayed on orotherwise formed directly on the internal surface 104 a of the well 104or a preceding layer of the insulating liner 106. Even though particularlayers and arrangements of the layers are illustrated in FIGS. 2A-2C, insome embodiments, one or more of the protection layer 124, sealing layer128, or perfusion layer 130 may be omitted.

The protection layer can be configured to at least reduce an impact ofphysical damage, such as punctures scraping, or other suitable types ofmechanical damages, to the insulating layer 126. For example, theprotection layer 124 can include one or more protection materialsconfigured to protect the insulating layer 126 from perforation, causedby, for instance, contact with servers 103 and/or the rack 101 (FIG. 1)during installation or maintenance. Examples of suitable protectionmaterials can include Nylon, Kevlar, Ultra high molecular weightpolyethylene, silk, carbon fibers, or combinations of at least some ofthe foregoing protection materials.

The sealing layer 128 can include one or more sealing materials that areconfigured to automatically seal the insulating layer 126 in case of aperforation is formed in the insulating layer 126. Examples of suitablesealing materials can include ballistic gelatins, multiple strata ofrubber coating, or other suitable sealant that can automatically expandand/or contract to seal a perforation. Though the sealing layer 128 isshown being between the insulating layer 126 and the perfusion layer 130in FIG. 2A, in other embodiments, the sealing layer 128 can also bespaced apart from the insulating layer 126 by, for instance, anintermediate layer (not shown). In further embodiments, the sealinglayer 128 may have other suitable configurations or being omitted fromthe insulating liner 106.

The perfusion layer 130 can be configured to remove and thus allowdetections of any leaked dielectric coolant 120 through the insulatinglayer 126 (as illustrated with the dashed arrow). For example, as shownin FIGS. 2B and 2C, the perfusion layer 130 can include a base 132having multiple ribs or other suitable types of protrusions (referred toherein as “ribs 134” for simplicity) extending from the base. Adjacentpairs of the multiple ribs 134 can then form multiple channels 136 (fourare shown in FIG. 2C for illustration purposes) in fluid communicationwith a vacuum source (not shown). As such, when the perfusion layer 130is positioned behind and/or attached to the insulating layer 126 (shownin FIG. 2A), with or without intermediate layer(s), any leakeddielectric coolant 120 can be removed from behind the insulating layer126. By monitoring output from the perfusion layer 130, leak detectionof the dielectric coolant 120 from the well 104 can be achieved usingcolor changing paints, sensors, or other suitable detectors. In otherexamples, the perfusion layer 130 can also include a top (not shown)opposite the base 132 such that the multiple ribs 134 extend between thetop and the base 132. In further examples, the perfusion layer 130 canbe a built-in layer at the insulating layer 126, sealing layer 128, orother suitable layers of the insulating liner 106.

FIG. 3 is schematic cross-sectional view of a lid 108 suitable for theimmersion cooling enclosure 102 in FIG. 1 in accordance with additionalembodiments of the disclosed technology. As shown in FIG. 3, the lid 108can include a top portion 108 a opposite a bottom portion 108 bpartially enclosing a portion of the vapor space 122 in the well 104.The lid 108 can also include one or more filter layers 140 extendingbetween the top portion 108 a and the bottom portion 108 b in the vaporspace 122. An example material suitable for the filter layer includesactivated carbon. In the illustrated example, the lid 108 includes firstand second filter layers 140 and 140′ arranged in sequence. The firstfilter layer 140 is positioned in the vapor space 122 while the secondfilter layer 140′ is positioned at a vapor outlet 108 c of the lid 108.A secondary condenser 110′ is positioned between the first and secondfilter layers 140 and 140′. In other examples, the lid 108 can includeone, three, four, or any suitable numbers of filter layers 140 with orwithout intermediate secondary condensers 110′.

As shown in FIG. 3, during operation, the dielectric coolant 120 can atleast partially boil and escape into the vapor space 122 of the well 104as a vapor of the dielectric coolant 120 (as illustrated with the arrow150 a). The vapor then contacts the condenser 110 (as illustrated by thearrow 150 b). The cooling fluid (not shown) flowing through thecondenser 110 can then remove heat from the vapor and condenses thevapor into a liquid, which then returns to the well 104 via gravity (asillustrated by the arrow 150 c) or pump.

During the foregoing operation, air containing the vapor of thedielectric coolant 120 can contact the filter layer 140. The filterlayer 140 can then allow air to pass through the filter layer 140without allowing or at least reducing permeability of the vapor of thedielectric coolant 120 through the filter layer 140. The air with atleast a reduced amount of the vapor of the dielectric coolant 120 canthen contact the secondary condenser 110′, which condenses and returnsto the well 104 any remaining dielectric coolant 120 in the air. The airthen passes through the secondary condenser 110′ and is withdrawn fromthe vapor space 122 of the well 104 via the second filter layer 140′. Assuch, air may be withdrawn/introduced from/to the vapor space 122 of thewell 104 to control pressure in the well 104 without losing a largeamount of the dielectric coolant 120. The withdrawn air can also befurther condensed to recover any dielectric coolant 120 still presentand return to a collection reservoir (not shown) and/or the well 104via, for instance, a circulation pump (not shown). In yet furtherexamples, multiple filter layers 140 and/or condensers 110 may bearranged in sequence, interleaved, or other suitable manners between thevapor space 122 and the vapor outlet 108 c.

FIG. 4 is a flowchart illustrating an example process 200 of deployingan immersion cooling enclosure of the insulated-well design of FIG. 1 inaccordance with embodiments of the disclosed technology. As shown inFIG. 4, the process 200 can include forming a well at stage 202. Exampletechniques for forming the well are described above with reference toFIG. 1. The process 200 can then include installing an insulation linerin the formed well at stage 204. As discussed in more detail above withreference to FIGS. 1-2C, the insulation liner can include at least oneinsulating layer that is configured to prevent a dielectric coolant fromleaking through the formed well. The process 200 can then includeloading servers and/or racks supporting the servers into the well atstage 206. For example, a rack or other suitable types of supportingdevice can be placed inside the well and in contact with the insulationliner in the well. The rack can also include a protection layer atsurfaces that contact or come in close proximity to the insulationliner. The process 200 can then include covering the well with a lid andsealing the well from outside and filling the well with the dielectriccoolant to fully submerge the servers carried on the rack at stage 208.

From the foregoing, it will be appreciated that specific embodiments ofthe disclosure have been described herein for purposes of illustration,but that various modifications may be made without deviating from thedisclosure. In addition, many of the elements of one embodiment may becombined with other embodiments in addition to or in lieu of theelements of the other embodiments. Accordingly, the technology is notlimited except as by the appended claims.

We claim:
 1. An insulated-well immersion cooling enclosure, comprising:a well formed in a substrate material, the well having a first surfaceat a first elevation, a second surface at a second elevation that islower than the first elevation, and side surfaces extending between thefirst and second surfaces; a lid in contact with and fastened to thefirst surface of the well, the lid, the second surface of the well, andthe side surfaces of the well enclosing an internal space configured tocontain a dielectric coolant submerging one or more computing devices inthe internal space; and an insulating liner on the second surface andthe side surfaces of the well, the insulating liner having a first sidein contact with the dielectric coolant and a second side in contact withthe substrate material at the second surface and the side surfaces ofthe well, wherein the insulating liner is non-permeable to thedielectric coolant, thereby preventing the dielectric coolant frompassing through the insulating liner to the substrate material.
 2. Theinsulated-well immersion cooling enclosure of claim 1 wherein theinsulating liner includes an insulating layer constructed from apolymeric material that is non-permeable to the dielectric coolant. 3.The insulated-well immersion cooling enclosure of claim 1 wherein theinsulating liner includes: an insulating layer constructed from apolymeric material that is non-permeable to the dielectric coolant; anda protection layer between the insulating layer and the dielectriccoolant, the protection layer being constructed from one or more ofNylon, Kevlar, ultra-high molecular weight polyethylene, silk, or carbonfibers.
 4. The insulated-well immersion cooling enclosure of claim 1wherein the insulating liner includes: an insulating layer constructedfrom a polymeric material that is non-permeable to the dielectriccoolant; a protection layer between the insulating layer and thedielectric coolant, the protection layer being constructed from one ormore of Nylon, Kevlar, ultra-high molecular weight polyethylene, silk,or carbon fibers; and a sealing layer between the insulating layer andthe substrate material of the well, the sealing layer being constructedfrom one or more of a ballistic gelatin or multiple strata of rubber. 5.The insulated-well immersion cooling enclosure of claim 1 wherein theinsulating liner includes: an insulating layer constructed from apolymeric material that is non-permeable to the dielectric coolant; anda perfusion layer between the insulating layer and the substratematerial of the well, the perfusion layer including one or more channelsin fluid communication with a vacuum source configured to remove anydielectric coolant passing through the insulating layer.
 6. Theinsulated-well immersion cooling enclosure of claim 1 wherein theinsulating liner includes: an insulating layer constructed from apolymeric material that is non-permeable to the dielectric coolant; anda perfusion layer between the insulating layer and the substratematerial of the well, the perfusion layer including a base havingmultiple protrusions extending toward the insulating layer, whereinadjacent pairs of protrusions form multiple channels in fluidcommunication with a vacuum source configured to remove any dielectriccoolant passing through the insulating layer.
 7. The insulated-wellimmersion cooling enclosure of claim 1 wherein the lid includes acondenser in thermal communication with the internal space, thecondenser being configured to remove heat from a vapor of the dielectriccoolant, thereby condensing the vapor of the dielectric coolant into aliquid returned to the internal space via gravity or pump.
 8. Theinsulated-well immersion cooling enclosure of claim 1 wherein the lidincludes: a condenser in thermal communication with the internal space,the condenser being configured to remove heat from a vapor of thedielectric coolant, thereby condensing the vapor of the dielectriccoolant into a liquid returned to the internal space via gravity orpump; a vapor outlet from the internal space of the immersion coolingenclosure; and a filter layer between the vapor outlet and thecondenser, the filter layer being configured to allow air to passthrough but not the vapor of the dielectric coolant.
 9. Theinsulated-well immersion cooling enclosure of claim 1 wherein the lidincludes: a vapor outlet from the internal space of the immersioncooling enclosure; a first condenser; a second condenser between thefirst condenser and the vapor outlet, the first and second condensersboth being in thermal communication with the internal space andconfigured to remove heat from a vapor of the dielectric coolant,thereby condensing the vapor of the dielectric coolant into a liquidreturned to the internal space of the immersion cooling enclosure viagravity or pump; and a filter layer between the first and secondcondensers, the filter layer being configured to allow air to passthrough but not the vapor of the dielectric coolant, the filter layerbeing constructed from carbon.
 10. The insulated-well immersion coolingenclosure of claim 1 wherein the lid includes: a vapor outlet from theinternal space of the immersion cooling enclosure; a first condenser; asecond condenser between the first condenser and the vapor outlet, thefirst and second condensers both being in thermal communication with theinternal space and configured to remove heat from a vapor of thedielectric coolant, thereby condensing the vapor of the dielectriccoolant into a liquid returned to the internal space of the immersioncooling enclosure via gravity or pump; and a first filter layer betweenthe first and second condensers; and a second filter layer at the vaporoutlet, the first and second filter layers being configured to allow airto pass through but not the vapor of the dielectric coolant, the filterlayer being constructed from carbon.
 11. A computing facility,comprising: multiple immersion cooling enclosures individually having: awell formed in a substrate material, the well having a first surface ata first elevation, a second surface at a second elevation that is lowerthan the first elevation, and side surfaces extending between the firstand second surfaces; a lid in contact with and fastened to the firstsurface of the well, the lid, the second surface of the well, and theside surfaces of the well enclosing an internal space configured tocontain a dielectric coolant, the lid including a condenser in thermalcommunication with the internal space; and an insulating liner on thesecond surface and the side surfaces of the well, the insulating linerhaving a first side in contact with the dielectric coolant and a secondside in contact with the substrate material at the second surface andthe side surfaces of the well, wherein the insulating liner isnon-permeable to the dielectric coolant, thereby preventing thedielectric coolant from passing through the insulating liner to thesubstrate material; one or more servers in the internal space of theindividual immersion cooling enclosures, the one or more servers beingsubmerged in the dielectric coolant in the respective immersion coolingenclosures; and a manifold operatively coupled to the condensers of themultiple immersion cooling enclosures, the manifold being coupled to asource of cooling fluid.
 12. The computing facility of claim 11 whereinthe insulating liner includes an insulating layer constructed from apolymeric material that is non-permeable to the dielectric coolant. 13.The computing facility of claim 11 wherein the insulating linerincludes: an insulating layer constructed from a polymeric material thatis non-permeable to the dielectric coolant; and a protection layerbetween the insulating layer and the dielectric coolant, the protectionlayer being constructed from one or more of Nylon, Kevlar, ultra-highmolecular weight polyethylene, silk, or carbon fibers.
 14. The computingfacility of claim 11 wherein the insulating liner includes: aninsulating layer constructed from a polymeric material that isnon-permeable to the dielectric coolant; a protection layer between theinsulating layer and the dielectric coolant, the protection layer beingconstructed from one or more of Nylon, Kevlar, ultra-high molecularweight polyethylene, silk, or carbon fibers; and a sealing layer betweenthe insulating layer and the substrate material of the well, the sealinglayer being constructed from one or more of a ballistic gelatin ormultiple strata of rubber.
 15. The computing facility of claim 11wherein the insulating liner includes: an insulating layer constructedfrom a polymeric material that is non-permeable to the dielectriccoolant; a protection layer between the insulating layer and thedielectric coolant, the protection layer being constructed from one ormore of Nylon, Kevlar, ultra-high molecular weight polyethylene, silk,or carbon fibers; a sealing layer between the insulating layer and thesubstrate material of the well, the sealing layer being constructed fromone or more of a ballistic gelatin or multiple strata of rubber; and aperfusion layer between the insulating layer and the substrate materialof the well, the perfusion layer including one or more channels in fluidcommunication with a vacuum source configured to remove any dielectriccoolant passing through the insulating layer.
 16. The computing facilityof claim 11 wherein the insulating liner includes: an insulating layerconstructed from a polymeric material that is non-permeable to thedielectric coolant; a protection layer between the insulating layer andthe dielectric coolant, the protection layer being constructed from oneor more of Nylon, Kevlar, ultra-high molecular weight polyethylene,silk, or carbon fibers; a sealing layer between the insulating layer andthe substrate material of the well, the sealing layer being constructedfrom one or more of a ballistic gelatin or multiple strata of rubber;and a perfusion layer between the insulating layer and the substratematerial of the well, the perfusion layer including a base havingmultiple protrusions extending toward the insulating layer, whereinadjacent pairs of protrusions form multiple channels in fluidcommunication with a vacuum source configured to remove any dielectriccoolant passing through the insulating layer.
 17. The computing facilityof claim 10 wherein the lids of the immersion cooling enclosuresindividually include: a vapor outlet from the internal space of theimmersion cooling enclosure; and a filter layer between the vapor outletand the condenser, the filter layer being configured to allow air topass through but not the vapor of the dielectric coolant.
 18. A methodof forming immersion cooling enclosure for housing servers in acomputing facility, the method comprising: forming a well in a substratematerial, the well having a first surface at a first elevation, a secondsurface at a second elevation that is lower than the first elevation,and side surfaces extending between the first and second surfaces;placing an insulating liner on the second surface and the side surfacesof the well, the insulating liner having a first side and a second sideopposite the first side and in contact with the substrate material atthe second surface and the side surfaces of the well; positioning one ormore servers in the well, the one or more servers being separated fromthe substrate material of the well by the insulating liner; sealing theone or more servers in the formed well with a lid in contact with thefirst surface of the well, the lid, the second surface of the well, andthe side surfaces of the well enclosing an internal space; and fillingthe internal space formed by the lid, the second surface of the well,and the side surfaces of the well with a dielectric coolant such thatthe one or more servers are submerged in the dielectric coolant.
 19. Themethod of claim 18 wherein placing the insulating liner includes one ormore of: fastening the insulating liner to the second surface and theside surfaces of the well via one or more of an adhesive or a mechanicalfastener; or spraying an insulating material of the insulating lineronto the second surface and the side surfaces of the well.
 20. Themethod of claim 18 wherein placing the insulating liner includes one ormore of: fastening the insulating liner to the second surface and theside surfaces of the well via one or more of an adhesive or a mechanicalfastener, the insulating liner including an insulating layer constructedfrom a polymeric material that is non-permeable to the dielectriccoolant and one or more of: a protection layer between the insulatinglayer and the dielectric coolant, the protection layer being constructedfrom one or more of Nylon, Kevlar, ultra-high molecular weightpolyethylene, silk, or carbon fibers; a sealing layer between theinsulating layer and the substrate material of the well, the sealinglayer being constructed from one or more of a ballistic gelatin ormultiple strata of rubber; or a perfusion layer between the insulatinglayer and the substrate material of the well, the perfusion layerincluding one or more channels in fluid communication with a vacuumsource configured to remove any dielectric coolant passing through theinsulating layer; or spraying a corresponding material of the insulatinglayer and one or more of the protection layer, the sealing layer, or theperfusion layer onto the second surface and the side surfaces of thewell or a preceding layer.